The present invention relates to a device for inhibiting aftercataract (hereinafter referred to as an inhibiting device) and more particularly to an inhibiting device for keeping a shape of a lenticular capsule substantially circular after a crystalline lens is removed and for preventing an invasion of epithelial cells into a posterior lenticular capsule, and further to an inhibiting device wherein an intraocular lens can be retained in good condition by forming a groove in an inner periphery thereof.
As an operation method of crystalline lens, the method, wherein an anterior lenticular capsule is provided with an opening and a crystalline lens is removed through the opening, has hitherto been employed. A refraction of an eye is corrected by inserting an intraocular lens into the lenticular capsule instead of the removed crystalline lens, wearing a contact lens on a cornea, or wearing a pair of spectacles.
When the intraocular lens is used, an intraocular lens such as lens 51 as shown in FIG. 18 has hitherto been used. The intraocular lens is composed of a lens 52 and two support members 53 having a wire like shape. The support member 53, wherein one end is fixed to the lens 52 and another end (outer side) is bended in such a manner as to extend along an equator of the lenticular capsule and contact with the equator, keeps the equator of the lenticular capsule circular. However, it is difficult for the above mentioned support member 53 to keep the equator of the lenticular capsule circular due to the shape thereof, and there is a danger that the support member adds an uneven force by partially contacting with the equator. Therefore, after inserting the intraocular lens into the lenticular capsule, the intraocular lens in the lenticular capsule becomes unstable after a long interval. Then, deviation or falling down of the intraocular lens sometimes happens.
The intraocular lenses 54, 55 shown in FIGS. 19 to 20 are proposed (with reference to Japanese Unexamined Patent Publication No. 285258/1989 and Japanese Unexamined Patent Publication No. 503525/1990). Each of the above lenses is composed of a lens portion 56, 57 and a support member 58, 59 which encloses the outer periphery of the lens portion having a circular loop like shape. The equator of the lenticular capsule can be kept to be circular in more preferable state compared with the intraocular lens of FIG. 18. It is difficult to insert the circular support member into the lenticular capsule through the incised opening as the original shape thereof. Therefore, the intraocular lens is inserted into the lenticular capsule by deflecting the support member to have an oval shape (referring to FIG. 19) or shrinking the support member in such a manner that circular shape thereof is kept (referring to FIG. 20).
The lenticular capsule after crystalline lens is removed sometimes happens to become opaque by proliferation, degeneration, or metaplasia of epithelial cells residual in the equator of the lenticular capsule if the capsule is left as it is. This phenomenon is generally called an aftercataract. A secondary operation typically needs to be performed to remove the aftercataract. As mentioned hereinbefore, when the intraocular lens is inserted into the lenticular capsule and the intraocular lens is fixed therein after the crystalline lens has been removed, there is such an intraocular lens as to inhibit the aftercataract to a certain extent by keeping the shape of the lenticular capsule and encircling the residual epithelial cell in the equator by virtue of the shape of the support member of the intraocular lens. However, the support member is not coming into contact with the whole part of the equator. Therefore, an aftercataract is not completely inhibited.
Further, when the lenticular capsule is left as it is for a long time without inserting the intraocular lens, the refraction of an eye should be corrected in such a manner that the contact lens is worn or a pair of spectacles is worn. In this case, an aftercataract is often produced in the lenticular capsule wherein the crystalline lens is removed. When the lenticular capsule is removed, such a complication that the vitreous body located in the back side of the eye goes forward is apt to come out. Accordingly, the lenticular capsule is not removed even if the intraocular lens is not inserted therein.
The object of the present invention is to resolve the problems mentioned hereinbefore and provide a device wherein an aftercataract is inhibited from forming and the circular shape of the equator can be kept stably.